In many universities you can do B.Sc (IT) and M.Sc (IT) after doing 12th Commerce with maths. Even if you do B.Com, you can still join MCA and do it. B.Tech is not the only avenue, so you don't
need to take science, though calculus does help in doing any serious computing work.
@tkin: To be fair, Chemical Engineering isn't really Chemistry - Chemistry is just a small part of it, hehehe
But I am surprised at you guys, saying 75 is low marks and all. Do you even know what kind of marks I used to get? My overall percentage was in the 70s when I passed - in my entire school life I have never scored 90+ in any subject except English. I had such middling marks, and 49 in my 10th standard out of 100. Nobody, and I mean nobody, thought I could do engineering. My entrance test marks were mediocre, to say the least. I didn't get the branch I wanted or a college that suited me.
I joined what was given to me, and it appears I have a degree in Electronics. My project is in Mechanics, my other small developed apparatus went into Instrumentation and Applied Physics. I also have an internship with a software company. I have had to work extra hard to secure myself but it was worth the ride. I have studied a little bit of many branches of engineering as a result of my extensive curiosity.
I do believe I suffered in the start because I never believed in coaching classes and have never attended any till date in my life, nor any concise notes from anyone (that's why I did badly in the entrance tests). But I have always given it my best shot.
If I, with my 49 in maths in my 10th standard, can belie all expectations and get through 4 years of engineering with a first class, do any of you really think you can't? Have faith in yourselves guys!
There have been times when my lack of academic prowess have been a hurdle - I have had to face many obstacles, because the system often thinks a person has no aptitude if he doesn't score the marks. I have had to face that kind of discrimination many times. Even today, people will ask me why I have that 49 in maths in my 10th when I have done much better in engineering mathematics.
But if students like us don't prove the system wrong, people will always be biased and think more marks = better. Have no fear, if you want to do something and you like to do it, join a course wherever you can, and do not worry about how difficult it seems. You will do well in time. This is the biggest advice I can give you